hörselbenen

The hörselbenen, or auditory ossicles, are the three tiny bones of the middle ear: malleus (hammer), incus (anvil), and stapes (stirrup). They form a connected lever system that transmits vibrations from the eardrum (tympanic membrane) to the inner ear via the oval window of the cochlea. The malleus is attached to the tympanic membrane and passes its motion to the incus, which then conveys it to the stapes, whose footplate contacts the oval window. This arrangement provides impedance matching between air and the fluid-filled inner ear, increasing the pressure of sound waves reaching the cochlea.

Two small muscles—the tensor tympani and the stapedius—attach to the ossicles and can adjust their stiffness. In response to loud sounds, the acoustic reflex contracts these muscles, reducing ossicle movement to protect the inner ear.

Disruptions of the ossicular chain, due to trauma or disease such as otosclerosis, can cause conductive hearing loss. Surgical procedures like stapedectomy or ossiculoplasty aim to restore the mechanical linkage and improve sound transmission. Developmentally, the auditory ossicles arise from neural crest and middle ear structures and are characteristic of the mammalian lineage, contributing to the efficiency of airborne sound detection.